1. Field Of The Invention
A fluid flow control device for use with a fluid circulating system to selectively control the direction of fluid flow through the fluid circulating system.
2. Description of The Prior Art
Most fluid pump systems include valve means to control the direction of fluid therethrough.
U.S. Pat. No. 4,019,680 discloses a steam boiler system including an automatic means for injecting cool water into a steam bound boiler feed pump. A first embodiment includes a pressure sensitive check valve to detect a drop of pressure in the steam bound pump and direct a cool water mist into the high side of the pump to reinitiate the operation of the pump. A second embodiment includes spraying cool water into the pump in response to a drop of the water level in the boiler. Both embodiments include a vent line to bleed the high side of the centrifugal pump to a condensate tank in response to a drop of pressure in the pump. The vent line may be bled through a check valve or directly through a manual valve. Each embodiment uses a pressure sensitive valve in the boiler feed line to stop the pump flow to the boiler whenever the pressure in the boiler exceeds the pressure at the output of the pump.
U.S. Pat. No. 1,993,267 shows a pump apparatus comprising a pipe including an enlarged area having a valve seat formed therein to selectively receive a ball valve held from accidental displacement by cross-rods or other suitable retaining means. The ball valve has a specific gravity such that at a predetermined water level in the reservoir the ball valve will remain unseated against the circulation caused by the suction at the discharge end. However, when the pump and reservoir are entirely filled with water and the ball valve is subjected to an upward pressure of the water in addition to the suction at the orifice of the nozzle, the ball valve will rise and seat to prevent re-circulation of the priming water in the reservoir.
U.S. Pat. No. 4,614,480 teaches a pump system including a ball check valve located downstream from a pump.
U.S. Pat. No. 3,644,061 discloses a pump apparatus including a one-way check valve in a discharge pipe to prevent air from returning to the pump.
An additional example of the prior art is found in U.S. Pat. No. 3,323,465.